1. Field of the Invention
The present invention relates to mechanical, cam-actuated clamping devices, and in particular to such clamping devices provided with a swinging clamp arm which moves from a first release position to a second position where the clamp is actuated to clamp a desired object.
2. Description of Related Art
Several types of clamps for clamping objects such as dies, fixtures, molds, and parts in machining operations are known. Such devices generally use hydraulic power to exert clamping force, but require continuous pressure application to maintain clamping. Some devices, like that disclosed in U.S. Pat. No. 4,721,293, teach the use of a hydraulic mechanism to close the clamp initially, but then uses a self-locking mechanism to eliminate the need for continued hydraulic pressure. JP 56-39846 also uses hydraulic power in combination with a mechanical lock. However, these clamping devices must be located or positioned manually, or by an auxiliary system, thereby increasing their operational change-over time and their cost of manufacture.
To eliminate such inefficiencies, swing clamps with a cam sleeve and/or a cam slot operated pneumatically, hydraulically, or manually are known, such as in U.S. Pat. No. 5,013,015. However, these devices do not exert locking forces as strong as those described above. However, those described previously do not present the benefit of a swinging clamp arm.
A device that provides a swing clamp arm and a strong locking force is disclosed in U.S. Pat. No. 4,830,349. However, it represents a relatively expensive concept and requires continuous pressure from a hydraulic pump for operation, resulting in additional operating costs from continuous operation and maintenance.